Barcelona have been hit with a 14-month transfer ban after Fifa ruled the club have fielded 10 ineligible youngsters.
The FIFA Disciplinary Committee ruled the Catalan giants registered and fielded non- Spanish players between 2009 and 2013 and will not be allowed to participate in the transfer market for two windows.
The committee said Barcelona had breached article 19 of the of the Regulations on the Status and Transfer of Players, which states that international transfers of players are only permitted if the player is over the age of 18.
The article is designed to protect youngsters from "social and legal issues" concerned with stakeholders in the game.
While it admitted some international transfers might be good for a player's sporting career, it concluded they are unlikely to be in the best interests of a young player.
As well as a CHF450,000 (£306,000) fine, the club has also been given 90 days to invesitgate the status of all players ages under 18 years old.
The affair began at the start of 2013, when Barcelona received a comminique from Fifa in which they prohibited the club from fielding Lee Seung Woo, a player dubbed 'the Korean Messi', whose transfer contravened article 19.
Fifa subsequently banned the Catalan club from fielding five other academy players, all of whose transfers violated the terms of the article.
Article 19 stipulates that under-18 players can only move countries under three conditions: if their parents relocate to the vicinity of the buying club for reasons unrelated to football; if the transfer is within the EU and the player is between 16 and 18; and if the player's home is less than 50km from his country's border, and the parent association of the buying club is a similar distance.
Barcelona disputed Fifa's ban, claiming that Barcelona deserved to be treated as a unique case because its famed academy educates young players in all players of life - personal, cultural, nutritional as well as sporting - in a top-quality facility designed to maximise the development of the individuals in its care.
Despite their attempt to challenge the ban, it appears Barca have adhered to its terms. Although Lee subsequently renewed his contract, the club said that he would only be playing in international tournaments, as he was banned from domestic matches under the terms of Fifa's order.
The ban has nothing to do with the financial problems surrounding Neymar, the Brazilian superstar whose transfer was blighted by tax irregularities.